Question

solve and give me the solution.​

Answer 1

Answer:

f(f(X))= X.

Step-by-step explanation:

$f(x) = \frac{px - q}{qx - p} \\ \\ f(f(x)) = \frac{p \frac{(px - q)}{(qx - p) } - q }{q \frac{(px - q)}{(qx - p)} - p} \\ \\ = \frac{ { {p}^{2} x + pq - {q}^{2} x }^{} + pq}{pqx - {q}^{2} - pqx + {p}^{2} } \\ \\ = \frac{x( {p}^{2} - {q}^{2}) }{( {p}^{2} - {q}^{2} ) } \\ \\ = x.$